Adding try/finally block

Hi,

I'm trying to add a try/finally block to every method in my system.
Unfortunately I have to do so, to ensure a counter to set/reset properly
in every case - i.e. normal execution of a method, exception raised in a
specific method (i.e. athrow executed in the same method) and methods
terminated by exception propagation.

Conceptually I'm trying to do the following:
methodStartLabel
...
<<<counter increment injected manually before every return statement
methodReturnStatement
<<<inject code here
<<<newTryBlockEndLabel
<<<counterIncrement
<<<athrowStatement
methodEndLabel


the TryCatckBlockNode is created with the following parameters:
methodStartLabel, newTryBlockEndLabel, newTryBlockEndlabel, null

For most cases I just don't use the visitor pattern, but inject the new
statements into the instruction list directly. Accordingly, I add the
TryCatchBlockNode just created into the tryCatchBlocks list. While
executing the instrumented application the following
NullPointerException is raised :( Any ideas or suggestions? I know there
is an example in one of the ASM papers related to my usecase.
Unfortunalty this doesn't help me a lot.

java.lang.NullPointerException
   at org.objectweb.asm.MethodWriter.visitMaxs(Unknown Source)
   at org.objectweb.asm.tree.MethodNode.accept(Unknown Source)
   at
de.kl.uni.cs.nehmer.setup.bci.SimpleBCIMethodAdapter.visitEnd(SimpleBCIMethodAdapter.java:51)
   at org.objectweb.asm.ClassReader.accept(Unknown Source)
   at org.objectweb.asm.ClassReader.accept(Unknown Source)
   at de.kl.uni.cs.nehmer.setup.bci.BCIAgent.transform(BCIAgent.java:32)
   at
sun.instrument.TransformerManager.transform(TransformerManager.java:169)
   at
sun.instrument.InstrumentationImpl.transform(InstrumentationImpl.java:365)
   at java.lang.ClassLoader.defineClass1(Native Method)
   at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
   at
java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
   at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
   at java.net.URLClassLoader.access$000(URLClassLoader.java:56)
   at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
   at java.security.AccessController.doPrivileged(Native Method)
   at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
   at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
   at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
   at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
   at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)

cheers Nikolas

-- 
You receive this message as a subscriber of the [email protected] mailing list.
To unsubscribe: mailto:[email protected]
For general help: mailto:[email protected]?subject=help
OW2 mailing lists service home page: http://www.ow2.org/wws